americanmcss

Hey everyone, Just got myself an 87 SR5 Ext Cab pickup last weekend and have begun the process of fixing the minor things that are wrong with it. Its a very nice little truck (all stock 160k original miles, near perfect interior). One of the problems I ran into was where the exhaust pipe was welded to the Y pipe which bolts to the exhaust manifold, the pipe had rusted and basically cracked off. After about 2 hours of fighting those pesky lock nuts that toyota used on there exhaust systems, and cutting the exhaust pipe and removing the manifold...we got it welded back up. Only to find that when I replaced the exhaust manifold (used a new manifold gasket as well - Fel Pro) I am getting a leak on the number 4 cylinder. Now my dumb a$$ did not think to inspect the manifold for cracks or breakage while it was off, so that is a possiblilty. All of my manifold nuts are tight but not too tight, so I was wondering if anyone has some suggestions of what to look for? Or maybe have faced this problem before. I would like to have some info in hand before I go and tear everything apart again...

Also, the truck has a catalytic converter on it...seems to be fairly new...not sure. Should I hack it off while Im working under there and reap the benefits of better flow? Cats aren't required where I live (not yet anyway). If worse comes to worse, I guess I could just throw a header on there. I know there are some decently priced brand name headers out there for around 150-175 dollars...any problems people have with those?

Thanks for the info.

cws9685

best thing to do is go with a header i had the same problem and that what did go with a pacesetter header it fits the best and for cutting the cat off you wont gane anything but better sound

Erik Beeman

keep that cat, KEEP THE CAT! I forwarned you

PismoJoe

Yes keep the cat, they put it there for a reason, and you can find a descent high-flow one for around $80 if yours needs replacing.

A header will not fix your exhaust leak, unless the stock manifold being warped is causing the leak. Fel-Pro exhaust gaskets are made with some fiber material that is far less superior than the stock exhaust manifold gasket. Still, you shouldn't have a leak this soon, so your manifold could very well be warped.

The bolts should be tightened right around 33ft/lbs, Don't over tighten them too much or snap and then your hating life.

In my case, the rear manifold studs were stripped, so the bolts kept backing off. Be careful if you have to replace the studs, removing them incorrectly or without patients can damage the brittle aluminum casting of your head, and then your once again hating life

americanmcss

Thanks for the advice... After doing a little more poking and prodding around, I'm pretty sure that there is a chunk of leftover gasket stuck to the head and that is whats causing the leak. As for the cat...yes it is there for a reason but that reason is not efficiency and performance. Not saying Im going to get rid of it yet, but if I dont need it, I dont really want it.

Swimmerboy2112

iTrader: (2)

If you get rid of it your exhaust will smell and it will sound like a tractor lol

americanmcss

...not exactly but ok.

barrel roll

Why?

The reason they are there is because of a stupid government regulation. You can get a car tuned without the catalytic converter to BEAT the exhaust specs of the stock vehicle equipt with one, but the regulation (and those that enforce it) are stuck on stupid.


The best exhaust gasket I've ever used is Copper High-Temp RTV.

PismoJoe

Hmmm you can lose your cat then if you prefer, note the WA smog standards are fairly high, not sure how they do in GA though

I wouldn't use RTV directly where the head meets the manifold, the only place I would use it is where the downpipe meets the manifold. You can re-use the o-ring gaskets with the use of some hi-temp RTV to ensure they seal back up

americanmcss

Actually, where I live, there are no real smog standards to speak of. If you really piss a cop off and he decides to see if your exhaust is modified, and finds that it is, he may write you up for it. Thats about all we deal with now in my county. The guy I bought it from lives closer to seattle where the greenies are in control and force even older vehicles to pass smog tests, so I got the paperwork with the truck.

PismoJoe

Nice, might want to look into how eliminating a cat messes with backflow, which these 4cyls are sensitive to. You could easily kill performance and MPG's if you simply do away with the cat.

Can you take off the cat? Since your smog laws allow it, then yes. What do you do about the change in backflow? I would look into the muffler company called "supertrapp" they have adjustable baffles so you can tweak with the proper amount of backflow to your specific application. I used one of these on an older toyota I had, and it sounded great and actually improved MPG's with this exhaust change.

Just a worthless opinion for you to throw around

barrel roll

In the case of the 4 stroke, the desire is to eliminate ALL the burned gasses from the cylinder when the piston gets to TDC - so the more backpressure, the higher the pressure will be inside the cylinder, and the less exhaust gas we will be able to expel. We don’t want those gasses inside the cylinder, so we want the backpressure on a 4 stroke to be as low as possible. Here’s a decent discussion on 4 strokes:
http://auto.howstuffworks.com/question172.htm

PismoJoe

Nice article, but there is more to back pressure than just the manifold.

You want proper exhaust gas reversion (exhaust gasses entering into a different exhaust runner or cylinder instead of exiting the system) to create enough "pull" as the exhaust gasses flow through the collector that a vacuum is created and gasses from the manifold are literally sucked out as they leave the cylinder head.

Anyways, take off the cat and check your MPG's and performance "gains" that people claim. Like I said, these 4cyl's are very sensitive to exhaust changes.

With that being said, if you want to take off a major part of the exhaust system that the 22R/RE was designed to use, go for it! It ain't my rig

americanmcss

Actually...

Barrel Roll has it right. You may want to do some research on exhaust scavenging... That has a lot to do with muffler placement and pipe diameter. Think about high performance engines...Nascar NHRA etc... those guys all run straight pipes and Im guessing its not just to make them loud.

PismoJoe

Did you just compare a 22R to a NHRA drag car?

Way different topics there in itself, I'm trying to speak from experience with 4cyl toyotas, but like I said its your rig so whatever you feel is right go for it

Trainwreckinseattle

1: I personally have never seen a flat 22r/22re manifold. They are all at least a little warped (like me) or cracked. I always surface them on our belt sander. This warping is also why I see a lot of broken or stripped out bolts at each end of the head. When the manifold warps it breaks them off or simply pulls them right out of the head.

2: I personally have seen flow tests of Factory manifolds and aftermarket headers. The ones tested matched so close it wasn't worth the money. More to the point a header unless properly wrapped with header tape will increase under hood temps by more than 50* and locally more than 120* This COOKS things like your brake fluid, brake booser diaphragm, spark plug wires, ignitor lead wire, etc. I have also seen things like vapor lock and other runability problems stem from this swap.

and 3: the 22R/22re is anemic at best, fooling with exhaust gets a person almost nowhere without many other changes as well.

americanmcss

Technically yes...literaly no. I know that there are vast diferences between the two.

americanmcss

I know that there are some differences in this article, and he does mention a lot of high performance vehicles and motorcycles, but this is a really good read about what we are talking about...

http://forum.concours.org/index.php?topic=45090

barrel roll

Still reading the other article posted, I just got home from the office.

What you experienced was loss of exhaust gas velocity, which is like a traffic jam in the exhaust side of the air pump we call an internal combustion engine. Every engine can receive this. If you have a SBC, don't make over 400 HP, and have larger than 2.5 inch dual exhaust or 3 (I think, I am a little fuzzy on single) single exhaust you will experience the same thing. TOO BIG is nearly the same (as bad) as TOO SMALL.

RustBucket

iTrader: (1)

Something to note when citing HowStuffWorks.com as a reference for technical questions:

http://www.howstuffworks.com/about-author.htm

I count about 50 English and journalism degrees, along with literature, creative writing, and even and Afro-American studies degrees. There's a contributing writer with a Ph.D. in physiology. Having trouble locating any science or engineering degrees though...